European Patent No. EP 2 192 063 (Giacobbe) discloses a pick-up head which has a support structure for holding a horizontal guide. Along the guide a plurality of pick-up devices are arranged side-by-side. The pick-up devices are operated to grip and release respective products and are moved along the guide by a moving assembly for varying the pitch between the pick-up devices. The moving assembly has a respective cam and a respective follower element for each pick-up device. The follower elements are coupled to the pick-up devices, respectively, while the cams are held by a drum which extends along an axis parallel to the horizontal guide and is activated by an actuator to rotate about the axis thereof.
U.S. Pat. No. 6,352,402 (Hwang et al.) describes an apparatus for adjusting a pitch of a picker using a single actuator. The apparatus includes a picker base, a plurality of pickers adapted for varying the pitch of the pickers by use of a linear guide device provided at one side of the picker base. The apparatus includes an actuator for driving the plurality of pickers, and a bevel gear unit coupled to the actuator by upper and lower racks for transmitting the driving force to the plurality of pickers.
Korean Patent Application No. KR 20080013529 (Lee et al.) describes an apparatus for inspecting and packing a semiconductor in a tray. The picking elements are arranged in two rows. A pantograph linkage between the picking elements enables an adjustment of the pitch.
A device tier adjusting a space between chips in a semiconductor chip tester, is disclosed in U.S. Pat. No. 6,068,317 (Park). A carrier plate is mounted movable along a horizontal guide rail. A mounting plate is fixed to the carrier plate and an elevating plate is mounted on the mounting plate movable in up and down direction. A cam shaft is rotatably mounted on the elevating plate. The cam shaft has a plurality of earn grooves formed in a radial direction in an outer circumferential surface. A plurality of pick-up members are fitted movable in a horizontal direction by a horizontal linear motion guider, which is inserted in a state atop of each of the pick-up members in one of the cam grooves.
PCT International Patent Application No. WO 2007/058076 (Yasuno) discloses a multiple nozzle unit with variable nozzle pitch. Each cylinder block shifts along a lateral bar, through an inclined grooved cam and a cam follower, by lifting a grooved cam body. The pitch of each nozzle is variably constituted.
U.S. Pat. No. 5,290,134 (Baba) shows a pick and place apparatus for use in an automatic test handler to pick up electronic devices from one type of tray. The electronic devices are placed in a predetermined position on the other tray for testing and sorting. The pick and place apparatus includes a plurality of suction inlets for picking up the electronic devices from the tray with suction power caused by a vacuum. A guide frame is used for slidably mounting the plurality of suction inlets in a horizontal direction. Furthermore, a mechanism is provided for adjusting the spacing of the suction inlets and to compensate for the differences in spacing between one tray and another tray.
U.S. Pat. No. 6,439,631 (Kress) discloses improved variable-pitch pick and place devices which may include one or more improvements such as a mechanical linkage such as pantograph linkage, the linkage itself linked to a plurality of device-gripping mechanisms arranged in a row so as to keep uniform, though variable, spacing between the device-gripping mechanisms, with the number of such mechanisms being increased relative to the number of parts in the linkage for reduced tolerance stack-up and improved positioning accuracy. The horizontal position of the linkage may be fixed at a position not at an end thereof, and desirably within the middle third or at the middle thereof. The linkage may be controlled at three points. These points may include a vertically flexible but horizontally fixed link to a supporting structure at the middle of the pantograph, a link at one end of the pantograph to one side of an endless loop of timing belt, and a link at tire other end of the pantograph to the other side of the endless loop of timing belt. The links to the timing belt at the ends of the pantograph may be made via two end-most device-gripping mechanisms. The position of the timing belt may be controlled by a servomotor with a position encoder, the servomotor controlled by a controller such as a computer. The device-gripping mechanisms may include a vacuum tip grounded and supplied with vacuum by an electrically-conductive vacuum tube.
Electronic components are often transported in Joint Electron Device Engineering Council (JEDEC) trays, which are molded matrix carriers, during the manufacturing process. The components are placed in the cells of the trays, and placing components in cells is usually done by pick and place robots. A pick and place robot typically has several grippers (or pickers) that can pick-up and remove an electronic component from a cell of a tray and also place an electronic component into a cell of a tray. The gripper may be mechanically clamping the electronic component or more commonly using vacuum nozzles.
In order to increase throughput, pick and place robots are often equipped with multiple grippers such that several components can be picked up or placed in parallel. Since components are of different sizes the number of components per tray row and column also differs and by that also the pitch between components. Therefore, the gripper pitch has to be adjustable and the number of grippers has to be adaptable. The grippers are commonly arranged in a row. In some cases, in particular for smaller components, two or more rows may be used in order to allow for further throughput increase. Ideally, the number of rows and the pitch between these rows would be adjustable as well.